Work conveyer for heat-treating furnaces



1953 w. H. HOLCROFT WORK CONVEYER FOR HEAT-TREATING FURNACES 4 Sheets-Sheet 1 Filed Nov. 24, 1952 INVENTOR.

WALTER H. HOLCROFT III- I L I I m J IQ\ ATTORNEYS Nov. 10, 1953 w. H. HOLCROFT WORK CONVEYER FOR HEAT-TREATING FURNACES 4 Sheets-Sheet 2 Filed Nov. 24, 1952 OHO R m m W.

WALTER H. HOLCROFT ATTORNEYS Nov. 10, 1953 Filed Nov. 24, 1952 w. H. HoLcR'o FT 2,658,633

WORK CONVEYER FOR HEAT-TREATING FURNACES 4 Sheets-Sheet 4 INVENTOR.

WALTER H. HOLCROFT ATTORNEYS Patented Nov. 10, 1953 WORK CONVEYER FOR HEAT-TREATING FURNACES Walter H. Holcroft, Detroit, Mich., assignor to Holcroft & Company, Detroit, Mich., a corporation of Michigan Application November 24, 1952, Serial No. 322,278

5 Claims.

The invention relates to work conveyors for use in heat treating furnaces and of that type which is commonly designated as walking-beam. Such construction includes parallelly arranged stationary rails extending longitudinally through the furnace chamber and one or more movable rails for periodically lifting the work from the stationary rails and advancing it a step. The movable rails are then depressed to redeposit the work on the stationary rails and while thus depressed are returned to the original position ready for advancing the work another step in a succeeding cycle. Conveyors of this type are particularly adapted for use with work pieces having a long dimension which extends transversely across the spaced rails. Such work pieces, as for instance shafts or axles, are advanced step by step through the entire length of the furnace chamber and at a rate which gives the desired length of time for heat treatment before removal from the furnace. However, a difficulty encountered is that the individual work pieces may shift slightly transversely of the rails during this step by step movement. This may result in contacting one end with some obstruction, such as a side wall of the furnace, which would disarrange the Whole series.

It is the object of the instant invention to prevent this creeping or misalignment of work pieces in the series and the invention consists in the construction for such purpose as hereinafter described.

In the drawings:

Figure 1 is a plan View of a work conveyor of the walking-beam type as arranged within a furnace chamber;

Figure 2 is a vertical longitudinal section through the furnace showing the conveyor and its operating mechanism in elevation;

Figure 3 is a cross-section through the furnace;

Figures 4, 5 and 6 are diagrammatic views illustrating the operation of the means for aligning the work on the conveyor.

Figure 7 is a side elevation of the mechanism at the left of Figure 3.

A is a furnace having a hearth portion A, side walls A and arched top A enclosing a furnace chamber. Within this chamber is a conveyor of the walking-beam type comprising spaced stationary rails B and B extending the entire length of the furnace chamber and movable rails C and C spaced to be on opposite sides of the rails B and B and arranged parallel thereto. The rails C and C are supported and actuated by mechanism including a series of supporting cross memhere D and hangers E and E connected to opposite ends of these cross members and extending upward through apertures F in the arched top of said furnace to be connected with mechanism thereabove. This mechanism includes a series of rock shafts G, one for each pair of hangers and having laterally extending rock arms G pivotally attached to the upper ends thereof. Each rock shaft is further provided with a pair of upwardly extending actuating rock arms G which are pivotally attached to a common actuating member extending longitudinally the entire length of the furnace. This member HH is composed of a plurality of short sections or links H pivotally attached to each other. At one end the member H is connected by a rod H with a rock arm I on a rock shaft I which is actuated by mechanism to be later described. The movable rails C, C are also connected at one end by links J with a reciprocating rod J extending through the end wall of the furnace and connected to mechanism for actuating the same. The construction as thus far described is such that the operation of the rock shaft I will impart simultaneous vertical movement to all of the hangers E and E, cross members D and rails C, C, While the rods J through their actuating mechanism will impart longitudinal reciprocation to said rails C, C in either the raised or lowered positions thereof. The normal position of the rails C and C is in a plane lower than that of the rails B and B and the cycle of operation includes, first, the raising of all of the hangers to lift the rails C, C above the rails B, B, lifting off any work supported on the latter; second, a longitudinal movement of the rails While in raised position; third, a lowering of the hangers to depress the rails C, C below the plane of the rails B, B; and fourth, a return longitudinal movement to their original position, which completes the cycle. It will also be understood that any work supported on the rails B, B and extending transversely thereof will be periodically lifted therefrom by the rails C, C, advanced a step and then redeposited on the rails B, B so that the work will be progressively advanced step by step the entire length of the furnace chamber.

For operating the rock shaft I and the rod J in properly timed relation to each other there is provided a mechanism F which includes an eccentric J 3 connected by a rod J to a rock arm I on the rock shaft I. There is also an eccentric J connected by a rod J to the rod J. While I have described a single set of rails B, B and C, 

